This invention relates to a latch assembly, and, more particularly, to a latch assembly which includes a latch which releases when a predetermined opening force is applied to it.
The latch assembly has particular utility with respect to containers, for example, picnic coolers, which include a cover or lid which is hingedly secured to a chest or container body. Such latch assemblies are desirably inexpensive, easy to assemble, and easy to operate, but they must also provide secure latching. Latches for picnic coolers must satisfy still another requirement--the latch must be releasable to permit the lid to open when a certain force is applied to the lid. This safeguards against the possiblity that a child could be trapped inside the cooler. A picnic cooler latch assembly should also require external manipulation in order to move the latch to the latched position and should have a minimum of protruding parts.
Some picnic cooler latches are attached at the front surface of the cooler and have hinged parts which may extend outwardly an inch or more and are thus subject to damage during normal use of the cooler. Other cooler latches have rigid outwardly protruding parts which may inflict pain if contacted during normal use. Picnic cooler latches which require several pounds of force to unlatch the lid require the user to hold the cooler enclosure with one hand while at the same time releasing the latch with the other hand.
U.S. Pat. No. 4,249,760 describes a picnic cooler latch assembly in which a sliding operating knob cams the latch into its latched and unlatched positions. The latch is flexible so that it releases when a sufficient opening force is applied. However, the bi-directional sliding movement of the knob may be confusing to some people.
The invention provides a latch assembly which releases when a predetermined opening force is applied, which automatically moves to the unlatched position when the closure is being shut, which requires external manipulation to move the latch to the latched position, and which requires only one continuous hand movement to first unlatch and then open the closure. The latch assembly includes a latch and a handle which are pivotally mounted on a closure for pivotal movement about parallel axes. A projection on the handle extends into a groove in the latch, and pivoting movement of the latch and the projection causes the latch to pivot. The projection and the groove move over a centerline between the two pivot axes, and the dimensions of the projection and the groove are such that a certain minimum force must be applied to move these parts over the centerline. The latch includes a pivot portion, a latching portion, and a connecting portion which joins the pivot portion and the latching portion. The connecting portion is flexible and permits the latching portion to move sufficiently to cause the latch to move over center to its unlatched position when a predetermined force is applied to the latching portion.